European Patent Application No. 360,358 describes a process for the preparation of polyketone fibers which are said to be useful as a reinforcing material. The fibers are made by successively spinning a solution of a polyketone, removing the solvent from the obtained fibers, and stretching the fibers at an elevated temperature. According to the specification and the Examples of European Patent Application No. 360 358, the solvents advantageously employed for preparing the polymer solution are hexafluoroisopropanol, m-cresol, and mixtures thereof. Moreover, minor amounts of compounds that are non-solvents for the polyketones may be employed in combination with the solvents mentioned hereinbefore. Such compounds include, among others, ketones such as acetone, with ethanol being mentioned as a preferred non-solvent. International Patent Application (PCT) No. WO 90/14453, published after the priority date of the present application, describes polyketone fibers and a method for the production of such fibers. The fibers are made by successively dissolving the polyketone in a suitable solvent, spinning the solution, removing all or some of the solvent from the spun fiber and stretching the fiber at elevated temperature. The solvent preferentially used for preparing the spinning solution is chosen from the group consisting of hexafluoroisopropanol, m-cresol, phenol, pyrrole, 2- chlorophenol, and 3-chlorophenol. A non-solvent for the polyketone may be used to stimulate the separation of the polyketone from the solvent in the spun object. Suitable non-solvents for this conversion are acetone, methyl ethyl ketone, and toluene. Although the processes of European Patent Application No. 360 358 and International Patent Application No. WO 90/14453 may provide polyketone fibers having properties which make them useful for some end-uses, improvements are desired with respect to the cost and the toxicity of the spinning solvents used, the speed of the spinning process, and the mechanical properties of the resulting fibers.